Environmental Chemistry is a relatively young science. Interest in this subject, however, is growing very rapidly and, although no agreement has been reached as yet about the exact content and limits of this interdisciplinary discipline, there appears to be increasing interest in seeing environmental topics which are based on chemistry embodied in this subject. One of the first objectives of Environmental Chemistry must be the study of the environment and of natural chemical processes which occur in the environment. A major purpose of this series on Environmental Chemistry, therefore, is to present a reasonably uniform view of various aspects of the chemistry of the environment and chemical reactions occurring in the environment. The industrial activities of man have given a new dimension to Environmental Chemistry. We have now synthesized and described over five million chemical compounds and chemical industry produces about hundred and fifty million tons of synthetic chemicals annually. We ship billions of tons of oil per year and through mining operations and other geophysical modifications, large quantities of inorganic and organic materials are released from their natural deposits. Cities and metropolitan areas ofup to 15 million inhabitants produce large quantities of waste in relatively small and confined areas. Much of the chemical products and waste products of modern society are released into the environment either during production, storage, transport, use or ultimate disposal. These released materials participate in natural cycles and reactions and frequently lead to interference and disturbance of natural systems.

The nature and scope of the text The environment in which we live has to a large extent been determined by the activities of innumerable organisms interacting with each other and with their immediate surroundings. From the point of view of the microbiologist, it is obvious that microbial activity has a great part to play in the continuing maintenance of conditions suitable for other forms of life on this planet. There has therefore always been an awareness of the need for a good understanding of how microorganisms react in the environ ment, and this has been heightened from time to time as detrimental microbial activities become evident under certain conditions. The need for a good understanding has recently assumed a new importance as the era of microbial manipulation dawns-microbiology has always been a practical discipline, and the possibilities of beneficial modification on a global scale may be within our grasp. The growing interest in environmental microbiology can be gauged from the increase in relevant undergraduate teaching. However, one of the most serious problems confronting the student is the dearth of appropriate texts. In part this is a reflection of the plethora of potential subject matter. The study of the relationships of microorganisms with each other and with their environments-"microbial ecology" -constitutes a subject area which is far from precisely circumscribed, and each researcher or teacher has his own personal notion of which topics are appropriate."